Nepheloturbidometry slideshare instrumental methods of analysis

Nepheloturbidometry slideshare instrumental methods of analysis

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  NEPHELOTURBIDOMETRY
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  INTRODUCTION • when electromagneticradiaton strikes on a particle in a solution ,some of the light will be absorbed by the particle ,some will be transmitted through the solution and some of the light will be scattered. • The amount of light scattered is prorportional to the concentration of insoluble particle. • scattered light is measured by Turbidimetry Nephelometer
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  Turbidimetry Turbidimerty deals withmeasurement of intensity of transmitted light. The intensity of transmitted light is inversely proportional to concentration of suspended particles.
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  Nephelometry Nephelometry deals withmeasurement of intensity of scattered light. The intensity of scattered light is proportional to concentration of suspended particles.
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  Instrumentation of Nepheloturbidometry 1.Radiationsource- Tungsten lamp or mercury arc lamp can be used.
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  2.Filter or Monochromator-converts polychromatic light into monochromatic light. 3.Sample Cell- also known as cuvette.It is made of glass and are rectangular in shape of width 1cm. 4.Detectors- 1.photovoltaic cell 2.phototubes 3.photomultiplier tube.
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  ▪ Factors affectingscattering of light- 1.Concentration of particles 2.Particle size 3.Molecular weight of particles 4.wavelength of radiation 1.Concentration of particles- Intensity of light is directly proportional to concentration of particles in sample solution. 2.Particle size- scattering of light depends upon size and shape of particles. The amount of scattering is directly proportional to square of effective radius of the particle. Smaller particles will cause symmetrical scattering of light. Larger particles will cause asymmetrical scattering of light.
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  3.Molecular weight ofparticles- Small molecular weight particles will cause less scattering of light while larger molecular weight particles will cause more light scattering. 4.Wavelenght of radiation- shorter wavelength radiations are scatter to greater extent while lomger wavelength scatter to lesser extent. Blue light scatter more than Red light.
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  Applications 1.Determination of particlesize present in suspensions. 2.Measurement of atmospheric pollutants. 3.Determinig concentration of solute in soution. 4.Determination of carbon dioxide, sugar products,and clarity of citric acid juices. 5.Biochemical analysis- measure the growth of bacterial cell in nutrient medium. 6. Coal, oil, rubber, plastic samples are analyzed by nepheloturbidimetry for estimation of sulphur content.
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